High frequency characteristics in low temperature pseudo-heterojunction bipolar transistors

Author

Miyamoto, Masafumi ; Yano, Kazuo ; Tamaki, Yoichi ; Aoki, Masaaki ; Nishida, Takashi ; Shimohigashi, Katsuhiro ; Seki, Koichi

Author_Institution

Hitachi Ltd., Tokyo, Japan

fYear

1990

fDate

17-18 Sep 1990

Firstpage

188

Lastpage

191

Abstract

A pseudo-HBT (heterojunction bipolar transistor) having a cutoff frequency (f_T) twice as high as that of a conventional bipolar transistor at 87 K is demonstrated. This is the first bipolar transistor that has a higher f_T below 100 K than at room temperature. The low-impurity-concentration graft base reduces the electron injection into the graft base, resulting in a high cutoff frequency. The impurity concentration of the graft base (extrinsic base) must be kept lower than that of the intrinsic base. In addition. the base profile must be kept as abrupt as possible to prevent the reduction of effective bandgap narrowing in the base

Keywords

cryogenics; heterojunction bipolar transistors; 87 K; HF characteristics; abrupt base profile; bandgap narrowing; cutoff frequency; extrinsic base; heterojunction bipolar transistor; low temperature; low-impurity-concentration graft base; pseudo HBT; Bipolar transistors; Capacitance; Circuits; Cutoff frequency; Degradation; Electrons; Equations; Impurities; Photonic band gap; Temperature dependence;

fLanguage

English

Publisher

ieee

Conference_Titel

Bipolar Circuits and Technology Meeting, 1990., Proceedings of the 1990

Conference_Location

Minneapolis, MN

Type

conf

DOI

10.1109/BIPOL.1990.171159

Filename

171159